Enhancing the compressive properties of re-entrant honeycombs by line defects with insight from nature

Abstract

Three novel heterogenous re-entrant honeycombs with possible applicability in the construction and automotive industries are designed with insight from geometric defects in cellular structures of nature (beehives and graphene). The honeycombs that are composed of geometric defect channels and the geometrically perfect honeycomb are produced via fused deposition modeling 3D printing method. The structures are tested via experimental and numerical methods and their behavior is assessed in terms of specific energy absorption (SEA), effective Young’s modulus (Ee), and deformation mechanism under compression. Each innovative structure outperforms the benchmark model in terms of Ee, owning a stiffer response to loading. Two of the defective honeycombs exhibit superior performance to the benchmark in terms of SEA, with about 100% and 157% higher specific energy absorption, due to having better stability and different lateral buckling modes under compression. Unlike the benchmark model, the defective honeycombs’ auxeticity is maintained under compression. Also, one of the parametric studies proves that the novel honeycombs have promising potential in applications where structures are subjected to inclined loads, due to having roughly 148% higher SEA than the benchmark under inclined compression.